This invention concerns an are loading system. More precisely, the invention concerns an are loading system for transferring fluid cargo between a cargo vessel and a cargo connection point at open sea where the cargo vessel is required to keep an end portion of the cargo vessel up towards the resultant element force direction. The invention also includes an are loading method.
The term “fluid” is as usually taken to include any liquid, gas and combinations thereof in any mixture.
A few loading systems for transferring fluids between installations and cargo vessel in open sea are known and well proven. So-called turret loading systems and bow loading systems may be the most well known.
EP 2500257 discloses a turret loading system, a vessel comprising a hull with a turret, a cavity in the turret and a mooring buoy releasably attached in the cavity. The buoy comprising a buoyant body and carrying a number of risers, extending to a subsea hydrocarbon well and a number of anchor lines connected to the sea bed, wherein upon connection of the buoy to the cavity, the buoy is attached to a pulling member connected to a winch on the vessel for lifting of the buoy.
U.S. Pat. No. 6,484,658 shows a bow loading arrangement for shuttle tankers where the mooring winch drum and hose handling winch drum are operated both together and independently of each other by the same drive unit. The winch may be placed on the main deck, and by using guide pulleys both the hose handling rope and the mooring hawser can be guided to the respective drums.
Common to these systems and other systems and methods are that the cargo vessel has to be adapted to the loading system. The cost of doing so may be substantial.
It is also known to utilize so-called tandem loading to a conventional cargo vessels by use of tugs and floating hose to the midship manifold of the vessel. However, the relatively long floating hose required results in quite high flow resistance.